19 files changed, 2001 insertions, 0 deletions

diff --git a/logic/net/ByteArrayDownload.cpp b/logic/net/ByteArrayDownload.cpp
new file mode 100644
index 00000000..27d2a250
--- /dev/null
+++ b/logic/net/ByteArrayDownload.cpp
@@ -0,0 +1,82 @@
+/* Copyright 2013 MultiMC Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "ByteArrayDownload.h"
+#include "MultiMC.h"
+#include "logger/QsLog.h"
+
+ByteArrayDownload::ByteArrayDownload(QUrl url) : NetAction()
+{
+	m_url = url;
+	m_status = Job_NotStarted;
+}
+
+void ByteArrayDownload::start()
+{
+	QLOG_INFO() << "Downloading " << m_url.toString();
+	QNetworkRequest request(m_url);
+	request.setHeader(QNetworkRequest::UserAgentHeader, "MultiMC/5.0 (Uncached)");
+	auto worker = MMC->qnam();
+	QNetworkReply *rep = worker->get(request);
+
+	m_reply = std::shared_ptr<QNetworkReply>(rep);
+	connect(rep, SIGNAL(downloadProgress(qint64, qint64)),
+			SLOT(downloadProgress(qint64, qint64)));
+	connect(rep, SIGNAL(finished()), SLOT(downloadFinished()));
+	connect(rep, SIGNAL(error(QNetworkReply::NetworkError)),
+			SLOT(downloadError(QNetworkReply::NetworkError)));
+	connect(rep, SIGNAL(readyRead()), SLOT(downloadReadyRead()));
+}
+
+void ByteArrayDownload::downloadProgress(qint64 bytesReceived, qint64 bytesTotal)
+{
+	m_total_progress = bytesTotal;
+	m_progress = bytesReceived;
+	emit progress(m_index_within_job, bytesReceived, bytesTotal);
+}
+
+void ByteArrayDownload::downloadError(QNetworkReply::NetworkError error)
+{
+	// error happened during download.
+	QLOG_ERROR() << "Error getting URL:" << m_url.toString().toLocal8Bit()
+				 << "Network error: " << error;
+	m_status = Job_Failed;
+}
+
+void ByteArrayDownload::downloadFinished()
+{
+	// if the download succeeded
+	if (m_status != Job_Failed)
+	{
+		// nothing went wrong...
+		m_status = Job_Finished;
+		m_data = m_reply->readAll();
+		m_reply.reset();
+		emit succeeded(m_index_within_job);
+		return;
+	}
+	// else the download failed
+	else
+	{
+		m_reply.reset();
+		emit failed(m_index_within_job);
+		return;
+	}
+}
+
+void ByteArrayDownload::downloadReadyRead()
+{
+	// ~_~
+}
diff --git a/logic/net/ByteArrayDownload.h b/logic/net/ByteArrayDownload.h
new file mode 100644
index 00000000..0d90abc2
--- /dev/null
+++ b/logic/net/ByteArrayDownload.h
@@ -0,0 +1,44 @@
+/* Copyright 2013 MultiMC Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+#include "NetAction.h"
+
+typedef std::shared_ptr<class ByteArrayDownload> ByteArrayDownloadPtr;
+class ByteArrayDownload : public NetAction
+{
+	Q_OBJECT
+public:
+	ByteArrayDownload(QUrl url);
+	static ByteArrayDownloadPtr make(QUrl url)
+	{
+		return ByteArrayDownloadPtr(new ByteArrayDownload(url));
+	}
+
+public:
+	/// if not saving to file, downloaded data is placed here
+	QByteArray m_data;
+
+public
+slots:
+	virtual void start();
+
+protected
+slots:
+	void downloadProgress(qint64 bytesReceived, qint64 bytesTotal);
+	void downloadError(QNetworkReply::NetworkError error);
+	void downloadFinished();
+	void downloadReadyRead();
+};
diff --git a/logic/net/CacheDownload.cpp b/logic/net/CacheDownload.cpp
new file mode 100644
index 00000000..d2a9bdee
--- /dev/null
+++ b/logic/net/CacheDownload.cpp
@@ -0,0 +1,169 @@
+/* Copyright 2013 MultiMC Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "MultiMC.h"
+#include "CacheDownload.h"
+#include <pathutils.h>
+
+#include <QCryptographicHash>
+#include <QFileInfo>
+#include <QDateTime>
+#include "logger/QsLog.h"
+
+CacheDownload::CacheDownload(QUrl url, MetaEntryPtr entry)
+	: NetAction(), md5sum(QCryptographicHash::Md5)
+{
+	m_url = url;
+	m_entry = entry;
+	m_target_path = entry->getFullPath();
+	m_status = Job_NotStarted;
+}
+
+void CacheDownload::start()
+{
+	m_status = Job_InProgress;
+	if (!m_entry->stale)
+	{
+		m_status = Job_Finished;
+		emit succeeded(m_index_within_job);
+		return;
+	}
+	// create a new save file
+	m_output_file.reset(new QSaveFile(m_target_path));
+
+	// if there already is a file and md5 checking is in effect and it can be opened
+	if (!ensureFilePathExists(m_target_path))
+	{
+		QLOG_ERROR() << "Could not create folder for " + m_target_path;
+		m_status = Job_Failed;
+		emit failed(m_index_within_job);
+		return;
+	}
+	if (!m_output_file->open(QIODevice::WriteOnly))
+	{
+		QLOG_ERROR() << "Could not open " + m_target_path + " for writing";
+		m_status = Job_Failed;
+		emit failed(m_index_within_job);
+		return;
+	}
+	QLOG_INFO() << "Downloading " << m_url.toString();
+	QNetworkRequest request(m_url);
+
+	// check file consistency first.
+	QFile current(m_target_path);
+	if(current.exists() && current.size() != 0)
+	{
+		if (m_entry->remote_changed_timestamp.size())
+			request.setRawHeader(QString("If-Modified-Since").toLatin1(),
+								m_entry->remote_changed_timestamp.toLatin1());
+		if (m_entry->etag.size())
+			request.setRawHeader(QString("If-None-Match").toLatin1(), m_entry->etag.toLatin1());
+	}
+
+	request.setHeader(QNetworkRequest::UserAgentHeader, "MultiMC/5.0 (Cached)");
+
+	auto worker = MMC->qnam();
+	QNetworkReply *rep = worker->get(request);
+
+	m_reply = std::shared_ptr<QNetworkReply>(rep);
+	connect(rep, SIGNAL(downloadProgress(qint64, qint64)),
+			SLOT(downloadProgress(qint64, qint64)));
+	connect(rep, SIGNAL(finished()), SLOT(downloadFinished()));
+	connect(rep, SIGNAL(error(QNetworkReply::NetworkError)),
+			SLOT(downloadError(QNetworkReply::NetworkError)));
+	connect(rep, SIGNAL(readyRead()), SLOT(downloadReadyRead()));
+}
+
+void CacheDownload::downloadProgress(qint64 bytesReceived, qint64 bytesTotal)
+{
+	m_total_progress = bytesTotal;
+	m_progress = bytesReceived;
+	emit progress(m_index_within_job, bytesReceived, bytesTotal);
+}
+
+void CacheDownload::downloadError(QNetworkReply::NetworkError error)
+{
+	// error happened during download.
+	QLOG_ERROR() << "Failed " << m_url.toString() << " with reason " << error;
+	m_status = Job_Failed;
+}
+void CacheDownload::downloadFinished()
+{
+	// if the download succeeded
+	if (m_status == Job_Failed)
+	{
+		m_output_file->cancelWriting();
+		m_reply.reset();
+		emit failed(m_index_within_job);
+		return;
+	}
+
+	// if we wrote any data to the save file, we try to commit the data to the real file.
+	if (wroteAnyData)
+	{
+		// nothing went wrong...
+		if (m_output_file->commit())
+		{
+			m_status = Job_Finished;
+			m_entry->md5sum = md5sum.result().toHex().constData();
+		}
+		else
+		{
+			QLOG_ERROR() << "Failed to commit changes to " << m_target_path;
+			m_output_file->cancelWriting();
+			m_reply.reset();
+			m_status = Job_Failed;
+			emit failed(m_index_within_job);
+			return;
+		}
+	}
+	else
+	{
+		m_status = Job_Finished;
+	}
+
+	// then get rid of the save file
+	m_output_file.reset();
+
+	QFileInfo output_file_info(m_target_path);
+
+	m_entry->etag = m_reply->rawHeader("ETag").constData();
+	if (m_reply->hasRawHeader("Last-Modified"))
+	{
+		m_entry->remote_changed_timestamp = m_reply->rawHeader("Last-Modified").constData();
+	}
+	m_entry->local_changed_timestamp =
+		output_file_info.lastModified().toUTC().toMSecsSinceEpoch();
+	m_entry->stale = false;
+	MMC->metacache()->updateEntry(m_entry);
+
+	m_reply.reset();
+	emit succeeded(m_index_within_job);
+	return;
+}
+
+void CacheDownload::downloadReadyRead()
+{
+	QByteArray ba = m_reply->readAll();
+	md5sum.addData(ba);
+	if (m_output_file->write(ba) != ba.size())
+	{
+		QLOG_ERROR() << "Failed writing into " + m_target_path;
+		m_status = Job_Failed;
+		m_reply->abort();
+		emit failed(m_index_within_job);
+	}
+	wroteAnyData = true;
+}
diff --git a/logic/net/CacheDownload.h b/logic/net/CacheDownload.h
new file mode 100644
index 00000000..154f5988
--- /dev/null
+++ b/logic/net/CacheDownload.h
@@ -0,0 +1,58 @@
+/* Copyright 2013 MultiMC Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include "NetAction.h"
+#include "HttpMetaCache.h"
+#include <QCryptographicHash>
+#include <QSaveFile>
+
+typedef std::shared_ptr<class CacheDownload> CacheDownloadPtr;
+class CacheDownload : public NetAction
+{
+	Q_OBJECT
+private:
+	MetaEntryPtr m_entry;
+	/// if saving to file, use the one specified in this string
+	QString m_target_path;
+	/// this is the output file, if any
+	std::shared_ptr<QSaveFile> m_output_file;
+	/// the hash-as-you-download
+	QCryptographicHash md5sum;
+
+	bool wroteAnyData = false;
+
+public:
+	explicit CacheDownload(QUrl url, MetaEntryPtr entry);
+	static CacheDownloadPtr make(QUrl url, MetaEntryPtr entry)
+	{
+		return CacheDownloadPtr(new CacheDownload(url, entry));
+	}
+	QString getTargetFilepath()
+	{
+		return m_target_path;
+	}
+protected
+slots:
+	virtual void downloadProgress(qint64 bytesReceived, qint64 bytesTotal);
+	virtual void downloadError(QNetworkReply::NetworkError error);
+	virtual void downloadFinished();
+	virtual void downloadReadyRead();
+
+public
+slots:
+	virtual void start();
+};
diff --git a/logic/net/ForgeMirror.h b/logic/net/ForgeMirror.h
new file mode 100644
index 00000000..2518dffe
--- /dev/null
+++ b/logic/net/ForgeMirror.h
@@ -0,0 +1,10 @@
+#pragma once
+#include <QString>
+
+struct ForgeMirror
+{
+	QString name;
+	QString logo_url;
+	QString website_url;
+	QString mirror_url;
+};
\ No newline at end of file
diff --git a/logic/net/ForgeMirrors.cpp b/logic/net/ForgeMirrors.cpp
new file mode 100644
index 00000000..b224306f
--- /dev/null
+++ b/logic/net/ForgeMirrors.cpp
@@ -0,0 +1,118 @@
+#include "MultiMC.h"
+#include "ForgeMirrors.h"
+#include "logger/QsLog.h"
+#include <algorithm>
+#include <random>
+
+ForgeMirrors::ForgeMirrors(QList<ForgeXzDownloadPtr> &libs, NetJobPtr parent_job,
+						   QString mirrorlist)
+{
+	m_libs = libs;
+	m_parent_job = parent_job;
+	m_url = QUrl(mirrorlist);
+	m_status = Job_NotStarted;
+}
+
+void ForgeMirrors::start()
+{
+	QLOG_INFO() << "Downloading " << m_url.toString();
+	QNetworkRequest request(m_url);
+	request.setHeader(QNetworkRequest::UserAgentHeader, "MultiMC/5.0 (Uncached)");
+	auto worker = MMC->qnam();
+	QNetworkReply *rep = worker->get(request);
+
+	m_reply = std::shared_ptr<QNetworkReply>(rep);
+	connect(rep, SIGNAL(downloadProgress(qint64, qint64)),
+			SLOT(downloadProgress(qint64, qint64)));
+	connect(rep, SIGNAL(finished()), SLOT(downloadFinished()));
+	connect(rep, SIGNAL(error(QNetworkReply::NetworkError)),
+			SLOT(downloadError(QNetworkReply::NetworkError)));
+	connect(rep, SIGNAL(readyRead()), SLOT(downloadReadyRead()));
+}
+
+void ForgeMirrors::downloadError(QNetworkReply::NetworkError error)
+{
+	// error happened during download.
+	QLOG_ERROR() << "Error getting URL:" << m_url.toString().toLocal8Bit()
+				 << "Network error: " << error;
+	m_status = Job_Failed;
+}
+
+void ForgeMirrors::downloadFinished()
+{
+	// if the download succeeded
+	if (m_status != Job_Failed)
+	{
+		// nothing went wrong... ?
+		parseMirrorList();
+		return;
+	}
+	// else the download failed, we use a fixed list
+	else
+	{
+		m_status = Job_Finished;
+		m_reply.reset();
+		deferToFixedList();
+		return;
+	}
+}
+
+void ForgeMirrors::deferToFixedList()
+{
+	m_mirrors.clear();
+	m_mirrors.append(
+		{"Minecraft Forge",				  "http://files.minecraftforge.net/forge_logo.png",
+		 "http://files.minecraftforge.net/", "http://files.minecraftforge.net/maven/"});
+	m_mirrors.append({"Creeper Host",
+					  "http://files.minecraftforge.net/forge_logo.png",
+					  "https://www.creeperhost.net/link.php?id=1",
+					  "http://new.creeperrepo.net/forge/maven/"});
+	injectDownloads();
+	emit succeeded(m_index_within_job);
+}
+
+void ForgeMirrors::parseMirrorList()
+{
+	m_status = Job_Finished;
+	auto data = m_reply->readAll();
+	m_reply.reset();
+	auto dataLines = data.split('\n');
+	for(auto line: dataLines)
+	{
+		auto elements = line.split('!');
+		if (elements.size() == 4)
+		{
+			m_mirrors.append({elements[0],elements[1],elements[2],elements[3]});
+		}
+	}
+	if(!m_mirrors.size())
+		deferToFixedList();
+	injectDownloads();
+	emit succeeded(m_index_within_job);
+}
+
+void ForgeMirrors::injectDownloads()
+{
+	// shuffle the mirrors randomly
+	std::random_device rd;
+	std::mt19937 rng(rd());
+	std::shuffle(m_mirrors.begin(), m_mirrors.end(), rng);
+
+	// tell parent to download the libs
+	for(auto lib: m_libs)
+	{
+		lib->setMirrors(m_mirrors);
+		m_parent_job->addNetAction(lib);
+	}
+}
+
+void ForgeMirrors::downloadProgress(qint64 bytesReceived, qint64 bytesTotal)
+{
+	m_total_progress = bytesTotal;
+	m_progress = bytesReceived;
+	emit progress(m_index_within_job, bytesReceived, bytesTotal);
+}
+
+void ForgeMirrors::downloadReadyRead()
+{
+}
diff --git a/logic/net/ForgeMirrors.h b/logic/net/ForgeMirrors.h
new file mode 100644
index 00000000..990e49d6
--- /dev/null
+++ b/logic/net/ForgeMirrors.h
@@ -0,0 +1,58 @@
+/* Copyright 2013 MultiMC Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include "NetAction.h"
+#include "HttpMetaCache.h"
+#include "ForgeXzDownload.h"
+#include "NetJob.h"
+#include <QFile>
+#include <QTemporaryFile>
+typedef std::shared_ptr<class ForgeMirrors> ForgeMirrorsPtr;
+
+class ForgeMirrors : public NetAction
+{
+	Q_OBJECT
+public:
+	QList<ForgeXzDownloadPtr> m_libs;
+	NetJobPtr m_parent_job;
+	QList<ForgeMirror> m_mirrors;
+
+public:
+	explicit ForgeMirrors(QList<ForgeXzDownloadPtr> &libs, NetJobPtr parent_job,
+						  QString mirrorlist);
+	static ForgeMirrorsPtr make(QList<ForgeXzDownloadPtr> &libs, NetJobPtr parent_job,
+								QString mirrorlist)
+	{
+		return ForgeMirrorsPtr(new ForgeMirrors(libs, parent_job, mirrorlist));
+	}
+
+protected
+slots:
+	virtual void downloadProgress(qint64 bytesReceived, qint64 bytesTotal);
+	virtual void downloadError(QNetworkReply::NetworkError error);
+	virtual void downloadFinished();
+	virtual void downloadReadyRead();
+
+private:
+	void parseMirrorList();
+	void deferToFixedList();
+	void injectDownloads();
+
+public
+slots:
+	virtual void start();
+};
diff --git a/logic/net/ForgeXzDownload.cpp b/logic/net/ForgeXzDownload.cpp
new file mode 100644
index 00000000..359ad858
--- /dev/null
+++ b/logic/net/ForgeXzDownload.cpp
@@ -0,0 +1,389 @@
+/* Copyright 2013 MultiMC Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "MultiMC.h"
+#include "ForgeXzDownload.h"
+#include <pathutils.h>
+
+#include <QCryptographicHash>
+#include <QFileInfo>
+#include <QDateTime>
+#include <QDir>
+#include "logger/QsLog.h"
+
+ForgeXzDownload::ForgeXzDownload(QString relative_path, MetaEntryPtr entry) : NetAction()
+{
+	m_entry = entry;
+	m_target_path = entry->getFullPath();
+	m_pack200_xz_file.setFileTemplate("./dl_temp.XXXXXX");
+	m_status = Job_NotStarted;
+	m_url_path = relative_path;
+}
+
+void ForgeXzDownload::setMirrors(QList<ForgeMirror> &mirrors)
+{
+	m_mirror_index = 0;
+	m_mirrors = mirrors;
+	updateUrl();
+}
+
+void ForgeXzDownload::start()
+{
+	m_status = Job_InProgress;
+	if (!m_entry->stale)
+	{
+		m_status = Job_Finished;
+		emit succeeded(m_index_within_job);
+		return;
+	}
+	// can we actually create the real, final file?
+	if (!ensureFilePathExists(m_target_path))
+	{
+		m_status = Job_Failed;
+		emit failed(m_index_within_job);
+		return;
+	}
+	if (m_mirrors.empty())
+	{
+		m_status = Job_Failed;
+		emit failed(m_index_within_job);
+		return;
+	}
+
+	QLOG_INFO() << "Downloading " << m_url.toString();
+	QNetworkRequest request(m_url);
+	request.setRawHeader(QString("If-None-Match").toLatin1(), m_entry->etag.toLatin1());
+	request.setHeader(QNetworkRequest::UserAgentHeader, "MultiMC/5.0 (Cached)");
+
+	auto worker = MMC->qnam();
+	QNetworkReply *rep = worker->get(request);
+
+	m_reply = std::shared_ptr<QNetworkReply>(rep);
+	connect(rep, SIGNAL(downloadProgress(qint64, qint64)),
+			SLOT(downloadProgress(qint64, qint64)));
+	connect(rep, SIGNAL(finished()), SLOT(downloadFinished()));
+	connect(rep, SIGNAL(error(QNetworkReply::NetworkError)),
+			SLOT(downloadError(QNetworkReply::NetworkError)));
+	connect(rep, SIGNAL(readyRead()), SLOT(downloadReadyRead()));
+}
+
+void ForgeXzDownload::downloadProgress(qint64 bytesReceived, qint64 bytesTotal)
+{
+	m_total_progress = bytesTotal;
+	m_progress = bytesReceived;
+	emit progress(m_index_within_job, bytesReceived, bytesTotal);
+}
+
+void ForgeXzDownload::downloadError(QNetworkReply::NetworkError error)
+{
+	// error happened during download.
+	// TODO: log the reason why
+	m_status = Job_Failed;
+}
+
+void ForgeXzDownload::failAndTryNextMirror()
+{
+	m_status = Job_Failed;
+	int next = m_mirror_index + 1;
+	if(m_mirrors.size() == next)
+		m_mirror_index = 0;
+	else
+		m_mirror_index = next;
+
+	updateUrl();
+	emit failed(m_index_within_job);
+}
+
+void ForgeXzDownload::updateUrl()
+{
+	QLOG_INFO() << "Updating URL for " << m_url_path;
+	for (auto possible : m_mirrors)
+	{
+		QLOG_INFO() << "Possible: " << possible.name << " : " << possible.mirror_url;
+	}
+	QString aggregate = m_mirrors[m_mirror_index].mirror_url + m_url_path + ".pack.xz";
+	m_url = QUrl(aggregate);
+}
+
+void ForgeXzDownload::downloadFinished()
+{
+	//TEST: defer to other possible mirrors (autofail the first one)
+	/*
+	QLOG_INFO() <<"dl " << index_within_job << " mirror " << m_mirror_index;
+	if( m_mirror_index == 0)
+	{
+		QLOG_INFO() <<"dl " << index_within_job << " AUTOFAIL";
+		m_status = Job_Failed;
+		m_pack200_xz_file.close();
+		m_pack200_xz_file.remove();
+		m_reply.reset();
+		failAndTryNextMirror();
+		return;
+	}
+	*/
+
+	// if the download succeeded
+	if (m_status != Job_Failed)
+	{
+		// nothing went wrong...
+		m_status = Job_Finished;
+		if (m_pack200_xz_file.isOpen())
+		{
+			// we actually downloaded something! process and isntall it
+			decompressAndInstall();
+			return;
+		}
+		else
+		{
+			// something bad happened -- on the local machine!
+			m_status = Job_Failed;
+			m_pack200_xz_file.remove();
+			m_reply.reset();
+			emit failed(m_index_within_job);
+			return;
+		}
+	}
+	// else the download failed
+	else
+	{
+		m_status = Job_Failed;
+		m_pack200_xz_file.close();
+		m_pack200_xz_file.remove();
+		m_reply.reset();
+		failAndTryNextMirror();
+		return;
+	}
+}
+
+void ForgeXzDownload::downloadReadyRead()
+{
+
+	if (!m_pack200_xz_file.isOpen())
+	{
+		if (!m_pack200_xz_file.open())
+		{
+			/*
+			* Can't open the file... the job failed
+			*/
+			m_reply->abort();
+			emit failed(m_index_within_job);
+			return;
+		}
+	}
+	m_pack200_xz_file.write(m_reply->readAll());
+}
+
+#include "xz.h"
+#include "unpack200.h"
+#include <stdexcept>
+
+const size_t buffer_size = 8196;
+
+void ForgeXzDownload::decompressAndInstall()
+{
+	// rewind the downloaded temp file
+	m_pack200_xz_file.seek(0);
+	// de-xz'd file
+	QTemporaryFile pack200_file("./dl_temp.XXXXXX");
+	pack200_file.open();
+
+	bool xz_success = false;
+	// first, de-xz
+	{
+		uint8_t in[buffer_size];
+		uint8_t out[buffer_size];
+		struct xz_buf b;
+		struct xz_dec *s;
+		enum xz_ret ret;
+		xz_crc32_init();
+		xz_crc64_init();
+		s = xz_dec_init(XZ_DYNALLOC, 1 << 26);
+		if (s == nullptr)
+		{
+			xz_dec_end(s);
+			failAndTryNextMirror();
+			return;
+		}
+		b.in = in;
+		b.in_pos = 0;
+		b.in_size = 0;
+		b.out = out;
+		b.out_pos = 0;
+		b.out_size = buffer_size;
+		while (!xz_success)
+		{
+			if (b.in_pos == b.in_size)
+			{
+				b.in_size = m_pack200_xz_file.read((char *)in, sizeof(in));
+				b.in_pos = 0;
+			}
+
+			ret = xz_dec_run(s, &b);
+
+			if (b.out_pos == sizeof(out))
+			{
+				if (pack200_file.write((char *)out, b.out_pos) != b.out_pos)
+				{
+					// msg = "Write error\n";
+					xz_dec_end(s);
+					failAndTryNextMirror();
+					return;
+				}
+
+				b.out_pos = 0;
+			}
+
+			if (ret == XZ_OK)
+				continue;
+
+			if (ret == XZ_UNSUPPORTED_CHECK)
+			{
+				// unsupported check. this is OK, but we should log this
+				continue;
+			}
+
+			if (pack200_file.write((char *)out, b.out_pos) != b.out_pos)
+			{
+				// write error
+				pack200_file.close();
+				xz_dec_end(s);
+				return;
+			}
+
+			switch (ret)
+			{
+			case XZ_STREAM_END:
+				xz_dec_end(s);
+				xz_success = true;
+				break;
+
+			case XZ_MEM_ERROR:
+				QLOG_ERROR() << "Memory allocation failed\n";
+				xz_dec_end(s);
+				failAndTryNextMirror();
+				return;
+
+			case XZ_MEMLIMIT_ERROR:
+				QLOG_ERROR() << "Memory usage limit reached\n";
+				xz_dec_end(s);
+				failAndTryNextMirror();
+				return;
+
+			case XZ_FORMAT_ERROR:
+				QLOG_ERROR() << "Not a .xz file\n";
+				xz_dec_end(s);
+				failAndTryNextMirror();
+				return;
+
+			case XZ_OPTIONS_ERROR:
+				QLOG_ERROR() << "Unsupported options in the .xz headers\n";
+				xz_dec_end(s);
+				failAndTryNextMirror();
+				return;
+
+			case XZ_DATA_ERROR:
+			case XZ_BUF_ERROR:
+				QLOG_ERROR() << "File is corrupt\n";
+				xz_dec_end(s);
+				failAndTryNextMirror();
+				return;
+
+			default:
+				QLOG_ERROR() << "Bug!\n";
+				xz_dec_end(s);
+				failAndTryNextMirror();
+				return;
+			}
+		}
+	}
+	m_pack200_xz_file.remove();
+
+	// revert pack200
+	pack200_file.seek(0);
+	int handle_in = pack200_file.handle();
+	// FIXME: dispose of file handles, pointers and the like. Ideally wrap in objects.
+	if(handle_in == -1)
+	{
+		QLOG_ERROR() << "Error reopening " << pack200_file.fileName();
+		failAndTryNextMirror();
+		return;
+	}
+	FILE * file_in = fdopen(handle_in,"r");
+	if(!file_in)
+	{
+		QLOG_ERROR() << "Error reopening " << pack200_file.fileName();
+		failAndTryNextMirror();
+		return;
+	}
+	QFile qfile_out(m_target_path);
+	if(!qfile_out.open(QIODevice::WriteOnly))
+	{
+		QLOG_ERROR() << "Error opening " << qfile_out.fileName();
+		failAndTryNextMirror();
+		return;
+	}
+	int handle_out = qfile_out.handle();
+	if(handle_out == -1)
+	{
+		QLOG_ERROR() << "Error opening " << qfile_out.fileName();
+		failAndTryNextMirror();
+		return;
+	}
+	FILE * file_out = fdopen(handle_out,"w");
+	if(!file_out)
+	{
+		QLOG_ERROR() << "Error opening " << qfile_out.fileName();
+		failAndTryNextMirror();
+		return;
+	}
+	try
+	{
+		unpack_200(file_in, file_out);
+	}
+	catch (std::runtime_error &err)
+	{
+		m_status = Job_Failed;
+		QLOG_ERROR() << "Error unpacking " << pack200_file.fileName() << " : " << err.what();
+		QFile f(m_target_path);
+		if (f.exists())
+			f.remove();
+		failAndTryNextMirror();
+		return;
+	}
+	pack200_file.remove();
+
+	QFile jar_file(m_target_path);
+
+	if (!jar_file.open(QIODevice::ReadOnly))
+	{
+		jar_file.remove();
+		failAndTryNextMirror();
+		return;
+	}
+	m_entry->md5sum = QCryptographicHash::hash(jar_file.readAll(), QCryptographicHash::Md5)
+						  .toHex()
+						  .constData();
+	jar_file.close();
+
+	QFileInfo output_file_info(m_target_path);
+	m_entry->etag = m_reply->rawHeader("ETag").constData();
+	m_entry->local_changed_timestamp =
+		output_file_info.lastModified().toUTC().toMSecsSinceEpoch();
+	m_entry->stale = false;
+	MMC->metacache()->updateEntry(m_entry);
+
+	m_reply.reset();
+	emit succeeded(m_index_within_job);
+}
diff --git a/logic/net/ForgeXzDownload.h b/logic/net/ForgeXzDownload.h
new file mode 100644
index 00000000..990f91f0
--- /dev/null
+++ b/logic/net/ForgeXzDownload.h
@@ -0,0 +1,65 @@
+/* Copyright 2013 MultiMC Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include "NetAction.h"
+#include "HttpMetaCache.h"
+#include <QFile>
+#include <QTemporaryFile>
+#include "ForgeMirror.h"
+
+typedef std::shared_ptr<class ForgeXzDownload> ForgeXzDownloadPtr;
+
+class ForgeXzDownload : public NetAction
+{
+	Q_OBJECT
+public:
+	MetaEntryPtr m_entry;
+	/// if saving to file, use the one specified in this string
+	QString m_target_path;
+	/// this is the output file, if any
+	QTemporaryFile m_pack200_xz_file;
+	/// mirror index (NOT OPTICS, I SWEAR)
+	int m_mirror_index = 0;
+	/// list of mirrors to use. Mirror has the url base
+	QList<ForgeMirror> m_mirrors;
+	/// path relative to the mirror base
+	QString m_url_path;
+
+public:
+	explicit ForgeXzDownload(QString relative_path, MetaEntryPtr entry);
+	static ForgeXzDownloadPtr make(QString relative_path, MetaEntryPtr entry)
+	{
+		return ForgeXzDownloadPtr(new ForgeXzDownload(relative_path, entry));
+	}
+	void setMirrors(QList<ForgeMirror> & mirrors);
+
+protected
+slots:
+	virtual void downloadProgress(qint64 bytesReceived, qint64 bytesTotal);
+	virtual void downloadError(QNetworkReply::NetworkError error);
+	virtual void downloadFinished();
+	virtual void downloadReadyRead();
+
+public
+slots:
+	virtual void start();
+
+private:
+	void decompressAndInstall();
+	void failAndTryNextMirror();
+	void updateUrl();
+};
diff --git a/logic/net/HttpMetaCache.cpp b/logic/net/HttpMetaCache.cpp
new file mode 100644
index 00000000..29007951
--- /dev/null
+++ b/logic/net/HttpMetaCache.cpp
@@ -0,0 +1,253 @@
+/* Copyright 2013 MultiMC Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "MultiMC.h"
+#include "HttpMetaCache.h"
+#include <pathutils.h>
+
+#include <QFileInfo>
+#include <QFile>
+#include <QTemporaryFile>
+#include <QSaveFile>
+#include <QDateTime>
+#include <QCryptographicHash>
+
+#include "logger/QsLog.h"
+
+#include <QJsonDocument>
+#include <QJsonArray>
+#include <QJsonObject>
+
+QString MetaEntry::getFullPath()
+{
+	return PathCombine(MMC->metacache()->getBasePath(base), path);
+}
+
+HttpMetaCache::HttpMetaCache(QString path) : QObject()
+{
+	m_index_file = path;
+	saveBatchingTimer.setSingleShot(true);
+	saveBatchingTimer.setTimerType(Qt::VeryCoarseTimer);
+	connect(&saveBatchingTimer, SIGNAL(timeout()), SLOT(SaveNow()));
+}
+
+HttpMetaCache::~HttpMetaCache()
+{
+	saveBatchingTimer.stop();
+	SaveNow();
+}
+
+MetaEntryPtr HttpMetaCache::getEntry(QString base, QString resource_path)
+{
+	// no base. no base path. can't store
+	if (!m_entries.contains(base))
+	{
+		// TODO: log problem
+		return MetaEntryPtr();
+	}
+	EntryMap &map = m_entries[base];
+	if (map.entry_list.contains(resource_path))
+	{
+		return map.entry_list[resource_path];
+	}
+	return MetaEntryPtr();
+}
+
+MetaEntryPtr HttpMetaCache::resolveEntry(QString base, QString resource_path,
+										 QString expected_etag)
+{
+	auto entry = getEntry(base, resource_path);
+	// it's not present? generate a default stale entry
+	if (!entry)
+	{
+		return staleEntry(base, resource_path);
+	}
+
+	auto &selected_base = m_entries[base];
+	QString real_path = PathCombine(selected_base.base_path, resource_path);
+	QFileInfo finfo(real_path);
+
+	// is the file really there? if not -> stale
+	if (!finfo.isFile() || !finfo.isReadable())
+	{
+		// if the file doesn't exist, we disown the entry
+		selected_base.entry_list.remove(resource_path);
+		return staleEntry(base, resource_path);
+	}
+
+	if (!expected_etag.isEmpty() && expected_etag != entry->etag)
+	{
+		// if the etag doesn't match expected, we disown the entry
+		selected_base.entry_list.remove(resource_path);
+		return staleEntry(base, resource_path);
+	}
+
+	// if the file changed, check md5sum
+	qint64 file_last_changed = finfo.lastModified().toUTC().toMSecsSinceEpoch();
+	if (file_last_changed != entry->local_changed_timestamp)
+	{
+		QFile input(real_path);
+		input.open(QIODevice::ReadOnly);
+		QString md5sum = QCryptographicHash::hash(input.readAll(), QCryptographicHash::Md5)
+							 .toHex()
+							 .constData();
+		if (entry->md5sum != md5sum)
+		{
+			selected_base.entry_list.remove(resource_path);
+			return staleEntry(base, resource_path);
+		}
+		// md5sums matched... keep entry and save the new state to file
+		entry->local_changed_timestamp = file_last_changed;
+		SaveEventually();
+	}
+
+	// entry passed all the checks we cared about.
+	return entry;
+}
+
+bool HttpMetaCache::updateEntry(MetaEntryPtr stale_entry)
+{
+	if (!m_entries.contains(stale_entry->base))
+	{
+		QLOG_ERROR() << "Cannot add entry with unknown base: "
+					 << stale_entry->base.toLocal8Bit();
+		return false;
+	}
+	if (stale_entry->stale)
+	{
+		QLOG_ERROR() << "Cannot add stale entry: " << stale_entry->getFullPath().toLocal8Bit();
+		return false;
+	}
+	m_entries[stale_entry->base].entry_list[stale_entry->path] = stale_entry;
+	SaveEventually();
+	return true;
+}
+
+MetaEntryPtr HttpMetaCache::staleEntry(QString base, QString resource_path)
+{
+	auto foo = new MetaEntry;
+	foo->base = base;
+	foo->path = resource_path;
+	foo->stale = true;
+	return MetaEntryPtr(foo);
+}
+
+void HttpMetaCache::addBase(QString base, QString base_root)
+{
+	// TODO: report error
+	if (m_entries.contains(base))
+		return;
+	// TODO: check if the base path is valid
+	EntryMap foo;
+	foo.base_path = base_root;
+	m_entries[base] = foo;
+}
+
+QString HttpMetaCache::getBasePath(QString base)
+{
+	if (m_entries.contains(base))
+	{
+		return m_entries[base].base_path;
+	}
+	return QString();
+}
+
+void HttpMetaCache::Load()
+{
+	QFile index(m_index_file);
+	if (!index.open(QIODevice::ReadOnly))
+		return;
+
+	QJsonDocument json = QJsonDocument::fromJson(index.readAll());
+	if (!json.isObject())
+		return;
+	auto root = json.object();
+	// check file version first
+	auto version_val = root.value("version");
+	if (!version_val.isString())
+		return;
+	if (version_val.toString() != "1")
+		return;
+
+	// read the entry array
+	auto entries_val = root.value("entries");
+	if (!entries_val.isArray())
+		return;
+	QJsonArray array = entries_val.toArray();
+	for (auto element : array)
+	{
+		if (!element.isObject())
+			return;
+		auto element_obj = element.toObject();
+		QString base = element_obj.value("base").toString();
+		if (!m_entries.contains(base))
+			continue;
+		auto &entrymap = m_entries[base];
+		auto foo = new MetaEntry;
+		foo->base = base;
+		QString path = foo->path = element_obj.value("path").toString();
+		foo->md5sum = element_obj.value("md5sum").toString();
+		foo->etag = element_obj.value("etag").toString();
+		foo->local_changed_timestamp = element_obj.value("last_changed_timestamp").toDouble();
+		foo->remote_changed_timestamp =
+			element_obj.value("remote_changed_timestamp").toString();
+		// presumed innocent until closer examination
+		foo->stale = false;
+		entrymap.entry_list[path] = MetaEntryPtr(foo);
+	}
+}
+
+void HttpMetaCache::SaveEventually()
+{
+	// reset the save timer
+	saveBatchingTimer.stop();
+	saveBatchingTimer.start(30000);
+}
+
+void HttpMetaCache::SaveNow()
+{
+	QSaveFile tfile(m_index_file);
+	if (!tfile.open(QIODevice::WriteOnly | QIODevice::Truncate))
+		return;
+	QJsonObject toplevel;
+	toplevel.insert("version", QJsonValue(QString("1")));
+	QJsonArray entriesArr;
+	for (auto group : m_entries)
+	{
+		for (auto entry : group.entry_list)
+		{
+			QJsonObject entryObj;
+			entryObj.insert("base", QJsonValue(entry->base));
+			entryObj.insert("path", QJsonValue(entry->path));
+			entryObj.insert("md5sum", QJsonValue(entry->md5sum));
+			entryObj.insert("etag", QJsonValue(entry->etag));
+			entryObj.insert("last_changed_timestamp",
+							QJsonValue(double(entry->local_changed_timestamp)));
+			if (!entry->remote_changed_timestamp.isEmpty())
+				entryObj.insert("remote_changed_timestamp",
+								QJsonValue(entry->remote_changed_timestamp));
+			entriesArr.append(entryObj);
+		}
+	}
+	toplevel.insert("entries", entriesArr);
+	QJsonDocument doc(toplevel);
+	QByteArray jsonData = doc.toJson();
+	qint64 result = tfile.write(jsonData);
+	if (result == -1)
+		return;
+	if (result != jsonData.size())
+		return;
+	tfile.commit();
+}
diff --git a/logic/net/HttpMetaCache.h b/logic/net/HttpMetaCache.h
new file mode 100644
index 00000000..08b39fe2
--- /dev/null
+++ b/logic/net/HttpMetaCache.h
@@ -0,0 +1,75 @@
+/* Copyright 2013 MultiMC Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+#include <QString>
+#include <QMap>
+#include <qtimer.h>
+
+struct MetaEntry
+{
+	QString base;
+	QString path;
+	QString md5sum;
+	QString etag;
+	qint64 local_changed_timestamp = 0;
+	QString remote_changed_timestamp; // QString for now, RFC 2822 encoded time
+	bool stale = true;
+	QString getFullPath();
+};
+
+typedef std::shared_ptr<MetaEntry> MetaEntryPtr;
+
+class HttpMetaCache : public QObject
+{
+	Q_OBJECT
+public:
+	// supply path to the cache index file
+	HttpMetaCache(QString path);
+	~HttpMetaCache();
+
+	// get the entry solely from the cache
+	// you probably don't want this, unless you have some specific caching needs.
+	MetaEntryPtr getEntry(QString base, QString resource_path);
+
+	// get the entry from cache and verify that it isn't stale (within reason)
+	MetaEntryPtr resolveEntry(QString base, QString resource_path,
+							  QString expected_etag = QString());
+
+	// add a previously resolved stale entry
+	bool updateEntry(MetaEntryPtr stale_entry);
+
+	void addBase(QString base, QString base_root);
+
+	// (re)start a timer that calls SaveNow later.
+	void SaveEventually();
+	void Load();
+	QString getBasePath(QString base);
+public
+slots:
+	void SaveNow();
+
+private:
+	// create a new stale entry, given the parameters
+	MetaEntryPtr staleEntry(QString base, QString resource_path);
+	struct EntryMap
+	{
+		QString base_path;
+		QMap<QString, MetaEntryPtr> entry_list;
+	};
+	QMap<QString, EntryMap> m_entries;
+	QString m_index_file;
+	QTimer saveBatchingTimer;
+};
\ No newline at end of file
diff --git a/logic/net/MD5EtagDownload.cpp b/logic/net/MD5EtagDownload.cpp
new file mode 100644
index 00000000..63583e8d
--- /dev/null
+++ b/logic/net/MD5EtagDownload.cpp
@@ -0,0 +1,156 @@
+/* Copyright 2013 MultiMC Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "MultiMC.h"
+#include "MD5EtagDownload.h"
+#include <pathutils.h>
+#include <QCryptographicHash>
+#include "logger/QsLog.h"
+
+MD5EtagDownload::MD5EtagDownload(QUrl url, QString target_path) : NetAction()
+{
+	m_url = url;
+	m_target_path = target_path;
+	m_status = Job_NotStarted;
+}
+
+void MD5EtagDownload::start()
+{
+	QString filename = m_target_path;
+	m_output_file.setFileName(filename);
+	// if there already is a file and md5 checking is in effect and it can be opened
+	if (m_output_file.exists() && m_output_file.open(QIODevice::ReadOnly))
+	{
+		// get the md5 of the local file.
+		m_local_md5 =
+			QCryptographicHash::hash(m_output_file.readAll(), QCryptographicHash::Md5)
+				.toHex()
+				.constData();
+		m_output_file.close();
+		// if we are expecting some md5sum, compare it with the local one
+		if (!m_expected_md5.isEmpty())
+		{
+			// skip if they match
+			if(m_local_md5 == m_expected_md5)
+			{
+				QLOG_INFO() << "Skipping " << m_url.toString() << ": md5 match.";
+				emit succeeded(m_index_within_job);
+				return;
+			}
+		}
+		else
+		{
+			// no expected md5. we use the local md5sum as an ETag
+		}
+	}
+	if (!ensureFilePathExists(filename))
+	{
+		emit failed(m_index_within_job);
+		return;
+	}
+
+	QNetworkRequest request(m_url);
+
+	QLOG_INFO() << "Downloading " << m_url.toString() << " got " << m_local_md5;
+
+	if(!m_local_md5.isEmpty())
+	{
+		QLOG_INFO() << "Got " << m_local_md5;
+		request.setRawHeader(QString("If-None-Match").toLatin1(), m_local_md5.toLatin1());
+	}
+	if(!m_expected_md5.isEmpty())
+		QLOG_INFO() << "Expecting " << m_expected_md5;
+
+	request.setHeader(QNetworkRequest::UserAgentHeader, "MultiMC/5.0 (Uncached)");
+
+	// Go ahead and try to open the file.
+	// If we don't do this, empty files won't be created, which breaks the updater.
+	// Plus, this way, we don't end up starting a download for a file we can't open.
+	if (!m_output_file.open(QIODevice::WriteOnly))
+	{
+		emit failed(m_index_within_job);
+		return;
+	}
+
+	auto worker = MMC->qnam();
+	QNetworkReply *rep = worker->get(request);
+
+	m_reply = std::shared_ptr<QNetworkReply>(rep);
+	connect(rep, SIGNAL(downloadProgress(qint64, qint64)),
+			SLOT(downloadProgress(qint64, qint64)));
+	connect(rep, SIGNAL(finished()), SLOT(downloadFinished()));
+	connect(rep, SIGNAL(error(QNetworkReply::NetworkError)),
+			SLOT(downloadError(QNetworkReply::NetworkError)));
+	connect(rep, SIGNAL(readyRead()), SLOT(downloadReadyRead()));
+}
+
+void MD5EtagDownload::downloadProgress(qint64 bytesReceived, qint64 bytesTotal)
+{
+	m_total_progress = bytesTotal;
+	m_progress = bytesReceived;
+	emit progress(m_index_within_job, bytesReceived, bytesTotal);
+}
+
+void MD5EtagDownload::downloadError(QNetworkReply::NetworkError error)
+{
+	// error happened during download.
+	// TODO: log the reason why
+	m_status = Job_Failed;
+}
+
+void MD5EtagDownload::downloadFinished()
+{
+	// if the download succeeded
+	if (m_status != Job_Failed)
+	{
+		// nothing went wrong...
+		m_status = Job_Finished;
+		m_output_file.close();
+
+		// FIXME: compare with the real written data md5sum
+		// this is just an ETag
+		QLOG_INFO() << "Finished " << m_url.toString() << " got " << m_reply->rawHeader("ETag").constData();
+
+		m_reply.reset();
+		emit succeeded(m_index_within_job);
+		return;
+	}
+	// else the download failed
+	else
+	{
+		m_output_file.close();
+		m_output_file.remove();
+		m_reply.reset();
+		emit failed(m_index_within_job);
+		return;
+	}
+}
+
+void MD5EtagDownload::downloadReadyRead()
+{
+	if (!m_output_file.isOpen())
+	{
+		if (!m_output_file.open(QIODevice::WriteOnly))
+		{
+			/*
+			* Can't open the file... the job failed
+			*/
+			m_reply->abort();
+			emit failed(m_index_within_job);
+			return;
+		}
+	}
+	m_output_file.write(m_reply->readAll());
+}
diff --git a/logic/net/MD5EtagDownload.h b/logic/net/MD5EtagDownload.h
new file mode 100644
index 00000000..d5aed0ca
--- /dev/null
+++ b/logic/net/MD5EtagDownload.h
@@ -0,0 +1,51 @@
+/* Copyright 2013 MultiMC Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include "NetAction.h"
+#include <QFile>
+
+typedef std::shared_ptr<class MD5EtagDownload> Md5EtagDownloadPtr;
+class MD5EtagDownload : public NetAction
+{
+	Q_OBJECT
+public:
+	/// the expected md5 checksum. Only set from outside
+	QString m_expected_md5;
+	/// the md5 checksum of a file that already exists.
+	QString m_local_md5;
+	/// if saving to file, use the one specified in this string
+	QString m_target_path;
+	/// this is the output file, if any
+	QFile m_output_file;
+
+public:
+	explicit MD5EtagDownload(QUrl url, QString target_path);
+	static Md5EtagDownloadPtr make(QUrl url, QString target_path)
+	{
+		return Md5EtagDownloadPtr(new MD5EtagDownload(url, target_path));
+	}
+protected
+slots:
+	virtual void downloadProgress(qint64 bytesReceived, qint64 bytesTotal);
+	virtual void downloadError(QNetworkReply::NetworkError error);
+	virtual void downloadFinished();
+	virtual void downloadReadyRead();
+
+public
+slots:
+	virtual void start();
+};
diff --git a/logic/net/NetAction.h b/logic/net/NetAction.h
new file mode 100644
index 00000000..97c96e5d
--- /dev/null
+++ b/logic/net/NetAction.h
@@ -0,0 +1,89 @@
+/* Copyright 2013 MultiMC Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <QObject>
+#include <QUrl>
+#include <memory>
+#include <QNetworkReply>
+
+enum JobStatus
+{
+	Job_NotStarted,
+	Job_InProgress,
+	Job_Finished,
+	Job_Failed
+};
+
+typedef std::shared_ptr<class NetAction> NetActionPtr;
+class NetAction : public QObject
+{
+	Q_OBJECT
+protected:
+	explicit NetAction() : QObject(0) {};
+
+public:
+	virtual ~NetAction() {};
+
+public:
+	virtual qint64 totalProgress() const
+	{
+		return m_total_progress;
+	}
+	virtual qint64 currentProgress() const
+	{
+		return m_progress;
+	}
+	virtual qint64 numberOfFailures() const
+	{
+		return m_failures;
+	}
+public:
+	/// the network reply
+	std::shared_ptr<QNetworkReply> m_reply;
+
+	/// source URL
+	QUrl m_url;
+
+	/// The file's status
+	JobStatus m_status = Job_NotStarted;
+
+	/// index within the parent job
+	int m_index_within_job = 0;
+
+	qint64 m_progress = 0;
+	qint64 m_total_progress = 1;
+
+	/// number of failures up to this point
+	int m_failures = 0;
+
+signals:
+	void started(int index);
+	void progress(int index, qint64 current, qint64 total);
+	void succeeded(int index);
+	void failed(int index);
+
+protected
+slots:
+	virtual void downloadProgress(qint64 bytesReceived, qint64 bytesTotal) = 0;
+	virtual void downloadError(QNetworkReply::NetworkError error) = 0;
+	virtual void downloadFinished() = 0;
+	virtual void downloadReadyRead() = 0;
+
+public
+slots:
+	virtual void start() = 0;
+};
diff --git a/logic/net/NetJob.cpp b/logic/net/NetJob.cpp
new file mode 100644
index 00000000..9e800d13
--- /dev/null
+++ b/logic/net/NetJob.cpp
@@ -0,0 +1,112 @@
+/* Copyright 2013 MultiMC Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "NetJob.h"
+#include "pathutils.h"
+#include "MultiMC.h"
+#include "MD5EtagDownload.h"
+#include "ByteArrayDownload.h"
+#include "CacheDownload.h"
+
+#include "logger/QsLog.h"
+
+void NetJob::partSucceeded(int index)
+{
+	// do progress. all slots are 1 in size at least
+	auto &slot = parts_progress[index];
+	partProgress(index, slot.total_progress, slot.total_progress);
+
+	num_succeeded++;
+	QLOG_INFO() << m_job_name.toLocal8Bit() << "progress:" << num_succeeded << "/"
+				<< downloads.size();
+
+	if (num_failed + num_succeeded == downloads.size())
+	{
+		if (num_failed)
+		{
+			QLOG_ERROR() << m_job_name.toLocal8Bit() << "failed.";
+			emit failed();
+		}
+		else
+		{
+			QLOG_INFO() << m_job_name.toLocal8Bit() << "succeeded.";
+			emit succeeded();
+		}
+	}
+}
+
+void NetJob::partFailed(int index)
+{
+	auto &slot = parts_progress[index];
+	if (slot.failures == 3)
+	{
+		QLOG_ERROR() << "Part" << index << "failed 3 times (" << downloads[index]->m_url << ")";
+		num_failed++;
+		if (num_failed + num_succeeded == downloads.size())
+		{
+			QLOG_ERROR() << m_job_name.toLocal8Bit() << "failed.";
+			emit failed();
+		}
+	}
+	else
+	{
+		QLOG_ERROR() << "Part" << index << "failed, restarting (" << downloads[index]->m_url
+					 << ")";
+		// restart the job
+		slot.failures++;
+		downloads[index]->start();
+	}
+}
+
+void NetJob::partProgress(int index, qint64 bytesReceived, qint64 bytesTotal)
+{
+	auto &slot = parts_progress[index];
+
+	current_progress -= slot.current_progress;
+	slot.current_progress = bytesReceived;
+	current_progress += slot.current_progress;
+
+	total_progress -= slot.total_progress;
+	slot.total_progress = bytesTotal;
+	total_progress += slot.total_progress;
+	emit progress(current_progress, total_progress);
+}
+
+void NetJob::start()
+{
+	QLOG_INFO() << m_job_name.toLocal8Bit() << " started.";
+	m_running = true;
+	for (auto iter : downloads)
+	{
+		connect(iter.get(), SIGNAL(succeeded(int)), SLOT(partSucceeded(int)));
+		connect(iter.get(), SIGNAL(failed(int)), SLOT(partFailed(int)));
+		connect(iter.get(), SIGNAL(progress(int, qint64, qint64)),
+				SLOT(partProgress(int, qint64, qint64)));
+		iter->start();
+	}
+}
+
+QStringList NetJob::getFailedFiles()
+{
+	QStringList failed;
+	for (auto download : downloads)
+	{
+		if (download->m_status == Job_Failed)
+		{
+			failed.push_back(download->m_url.toString());
+		}
+	}
+	return failed;
+}
diff --git a/logic/net/NetJob.h b/logic/net/NetJob.h
new file mode 100644
index 00000000..03d6a36e
--- /dev/null
+++ b/logic/net/NetJob.h
@@ -0,0 +1,124 @@
+/* Copyright 2013 MultiMC Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+#include <QtNetwork>
+#include <QLabel>
+#include "NetAction.h"
+#include "ByteArrayDownload.h"
+#include "MD5EtagDownload.h"
+#include "CacheDownload.h"
+#include "HttpMetaCache.h"
+#include "ForgeXzDownload.h"
+#include "logic/tasks/ProgressProvider.h"
+
+class NetJob;
+typedef std::shared_ptr<NetJob> NetJobPtr;
+
+class NetJob : public ProgressProvider
+{
+	Q_OBJECT
+public:
+	explicit NetJob(QString job_name) : ProgressProvider(), m_job_name(job_name) {};
+
+	template <typename T> bool addNetAction(T action)
+	{
+		NetActionPtr base = std::static_pointer_cast<NetAction>(action);
+		base->m_index_within_job = downloads.size();
+		downloads.append(action);
+		part_info pi;
+		{
+			pi.current_progress = base->currentProgress();
+			pi.total_progress = base->totalProgress();
+			pi.failures = base->numberOfFailures();
+		}
+		parts_progress.append(pi);
+		total_progress += pi.total_progress;
+		// if this is already running, the action needs to be started right away!
+		if (isRunning())
+		{
+			emit progress(current_progress, total_progress);
+			connect(base.get(), SIGNAL(succeeded(int)), SLOT(partSucceeded(int)));
+			connect(base.get(), SIGNAL(failed(int)), SLOT(partFailed(int)));
+			connect(base.get(), SIGNAL(progress(int, qint64, qint64)),
+					SLOT(partProgress(int, qint64, qint64)));
+			base->start();
+		}
+		return true;
+	}
+
+	NetActionPtr operator[](int index)
+	{
+		return downloads[index];
+	}
+	;
+	NetActionPtr first()
+	{
+		if (downloads.size())
+			return downloads[0];
+		return NetActionPtr();
+	}
+	int size() const
+	{
+		return downloads.size();
+	}
+	virtual void getProgress(qint64 &current, qint64 &total)
+	{
+		current = current_progress;
+		total = total_progress;
+	}
+	;
+	virtual QString getStatus() const
+	{
+		return m_job_name;
+	}
+	virtual bool isRunning() const
+	{
+		return m_running;
+	}
+	;
+	QStringList getFailedFiles();
+signals:
+	void started();
+	void progress(qint64 current, qint64 total);
+	void succeeded();
+	void failed();
+public
+slots:
+	virtual void start();
+	// FIXME: implement
+	virtual void abort() {};
+private
+slots:
+	void partProgress(int index, qint64 bytesReceived, qint64 bytesTotal);
+	void partSucceeded(int index);
+	void partFailed(int index);
+
+private:
+	struct part_info
+	{
+		qint64 current_progress = 0;
+		qint64 total_progress = 1;
+		int failures = 0;
+	};
+	QString m_job_name;
+	QList<NetActionPtr> downloads;
+	QList<part_info> parts_progress;
+	qint64 current_progress = 0;
+	qint64 total_progress = 0;
+	int num_succeeded = 0;
+	int num_failed = 0;
+	bool m_running = false;
+};
diff --git a/logic/net/PasteUpload.cpp b/logic/net/PasteUpload.cpp
new file mode 100644
index 00000000..fa54d084
--- /dev/null
+++ b/logic/net/PasteUpload.cpp
@@ -0,0 +1,86 @@
+#include "PasteUpload.h"
+#include "MultiMC.h"
+#include "logger/QsLog.h"
+#include <QJsonObject>
+#include <QJsonDocument>
+#include "gui/dialogs/CustomMessageBox.h"
+#include <QDesktopServices>
+
+PasteUpload::PasteUpload(QWidget *window, QString text) : m_text(text), m_window(window)
+{
+}
+
+void PasteUpload::executeTask()
+{
+	QNetworkRequest request(QUrl("http://paste.ee/api"));
+	request.setHeader(QNetworkRequest::UserAgentHeader, "MultiMC/5.0 (Uncached)");
+	QByteArray content(
+		"key=public&description=MultiMC5+Log+File&language=plain&format=json&paste=" +
+		m_text.toUtf8());
+	request.setRawHeader("Content-Type", "application/x-www-form-urlencoded");
+	request.setRawHeader("Content-Length", QByteArray::number(content.size()));
+
+	auto worker = MMC->qnam();
+	QNetworkReply *rep = worker->post(request, content);
+
+	m_reply = std::shared_ptr<QNetworkReply>(rep);
+	connect(rep, &QNetworkReply::downloadProgress, [&](qint64 value, qint64 max)
+	{ setProgress(value / max * 100); });
+	connect(rep, SIGNAL(error(QNetworkReply::NetworkError)), this,
+			SLOT(downloadError(QNetworkReply::NetworkError)));
+	connect(rep, SIGNAL(finished()), this, SLOT(downloadFinished()));
+}
+
+void PasteUpload::downloadError(QNetworkReply::NetworkError error)
+{
+	// error happened during download.
+	QLOG_ERROR() << "Network error: " << error;
+	emitFailed(m_reply->errorString());
+}
+
+void PasteUpload::downloadFinished()
+{
+	// if the download succeeded
+	if (m_reply->error() == QNetworkReply::NetworkError::NoError)
+	{
+		QByteArray data = m_reply->readAll();
+		m_reply.reset();
+		QJsonParseError jsonError;
+		QJsonDocument doc = QJsonDocument::fromJson(data, &jsonError);
+		if (jsonError.error != QJsonParseError::NoError)
+		{
+			emitFailed(jsonError.errorString());
+			return;
+		}
+		QString error;
+		if (!parseResult(doc, &error))
+		{
+			emitFailed(error);
+			return;
+		}
+	}
+	// else the download failed
+	else
+	{
+		emitFailed(QString("Network error: %1").arg(m_reply->errorString()));
+		m_reply.reset();
+		return;
+	}
+	emitSucceeded();
+}
+
+bool PasteUpload::parseResult(QJsonDocument doc, QString *parseError)
+{
+	auto object = doc.object();
+	auto status = object.value("status").toString("error");
+	if (status == "error")
+	{
+		parseError = new QString(object.value("error").toString());
+		return false;
+	}
+	// FIXME: not the place for GUI things.
+	QString pasteUrl = object.value("paste").toObject().value("link").toString();
+	QDesktopServices::openUrl(pasteUrl);
+	return true;
+}
+
diff --git a/logic/net/PasteUpload.h b/logic/net/PasteUpload.h
new file mode 100644
index 00000000..917a0016
--- /dev/null
+++ b/logic/net/PasteUpload.h
@@ -0,0 +1,26 @@
+#pragma once
+#include "logic/tasks/Task.h"
+#include <QMessageBox>
+#include <QNetworkReply>
+#include <memory>
+
+class PasteUpload : public Task
+{
+	Q_OBJECT
+public:
+	PasteUpload(QWidget *window, QString text);
+
+protected:
+	virtual void executeTask();
+
+private:
+	bool parseResult(QJsonDocument doc, QString *parseError);
+	QString m_text;
+	QString m_error;
+	QWidget *m_window;
+	std::shared_ptr<QNetworkReply> m_reply;
+public
+slots:
+	void downloadError(QNetworkReply::NetworkError);
+	void downloadFinished();
+};
diff --git a/logic/net/URLConstants.h b/logic/net/URLConstants.h
new file mode 100644
index 00000000..8cb1f3fd
--- /dev/null
+++ b/logic/net/URLConstants.h
@@ -0,0 +1,36 @@
+/* Copyright 2013 MultiMC Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <QString>
+
+namespace URLConstants
+{
+const QString AWS_DOWNLOAD_BASE("s3.amazonaws.com/Minecraft.Download/");
+const QString AWS_DOWNLOAD_VERSIONS(AWS_DOWNLOAD_BASE + "versions/");
+const QString AWS_DOWNLOAD_LIBRARIES(AWS_DOWNLOAD_BASE + "libraries/");
+const QString AWS_DOWNLOAD_INDEXES(AWS_DOWNLOAD_BASE + "indexes/");
+const QString ASSETS_BASE("assets.minecraft.net/");
+//const QString MCN_BASE("sonicrules.org/mcnweb.py");
+const QString RESOURCE_BASE("resources.download.minecraft.net/");
+const QString LIBRARY_BASE("libraries.minecraft.net/");
+const QString SKINS_BASE("skins.minecraft.net/MinecraftSkins/");
+const QString AUTH_BASE("authserver.mojang.com/");
+const QString FORGE_LEGACY_URL("http://files.minecraftforge.net/minecraftforge/json");
+const QString FORGE_GRADLE_URL("http://files.minecraftforge.net/maven/net/minecraftforge/forge/json");
+const QString MOJANG_STATUS_URL("http://status.mojang.com/check");
+const QString MOJANG_STATUS_NEWS_URL("http://status.mojang.com/news");
+}